DESCRIPTION: (Adapted from applicant's description) Several reproductive processes may be affected by nitric oxide (NO). Nitric oxide produced by cell specific isoforms of nitric oxide synthase (NOS) has been demonstrated to have putative role for the endothelial isoform (eNOS) in these processes. The researchers will compare follicular recruitment and ovulation at different times of the estrus cycle in wild type versus "knockout" animals with and without the use of drugs used for superovulation. Animals with varied Nos3 genotypes will be bred and evaluated for evidence of hypertension prior to and throughout gestation. Evidence for proteinuric hypertension (preeclampsia) will include laboratory assessment and pathologic survey of organs typically involved; promoter studies will be performed using a mouse genomic DNA clone containing 12 kilobases of the promoter region. Bovine and human umbilical endothelial cell cultures will be used to study the effects of estrogen and progesterone on Nos3 transcription, translation, and eNOS activity. The studies will establish that Nos3 is prone to induction when subjected to the hormonal milieu associated with reproductive processes. The investigators will proceed with sequence analysis and comparison with the human promoter region in an effort to understand the merits and limitations of this "knockout" as a model for the study of human disease and biology. Transiently transfected endothelial cells will be cultured with sex steroids to establish functional significance of specific murine promoter regions identified by sequence analysis.